Material working apparatus



8 Shets-Sheet 1 Filed Feb. 13, 1946 .Dec. 20, 1949 L. J. BULLIETMATERIAL WORKING APPARATUS 8 Sheets-Sheet 2 7 Filed Feb. 13, 1946 Dec.20, 1949 L. J. BULLIET l MATERIAL WORKING APPARATUS s Sheets-Sheet :5

Filed Feb. 15, 1946 NM N & mum ww ME QM 8m Q wk. 7 MN \M QM N WRN m g Qm NM QM Mi. QAN a, M, Wmw mum 8 I Mn- 2 @QM w wk ll q I m M I1 .111. T"[.1 l mum mmm f L Em FM Hbl \m c I|J\ L. Q h N ME 8% mm, LIN R mu M 91wmw m mam mw QM MMQM, m. QM an.

Dec. 20, 1949 L. J. BULLIET 2,492,092

MATERIAL WORKING APPARATUS Filed Feb. 13, 1946 8 Sheets-Sheet 4 Dec. 20,1949 1.. J. BULLIET 2,492,092

MATERIAL WORKING APPARATUS Filed Feb. 15, 1946 8 She'ets-Sheet 5 3J5 x300 flew Leander WW1 1949 L. J. BULLIET 2,492,092

MATERIAL WORKING APPARATUS 8 Sheets-Sheet 6 Filed Feb. 13, 1946 Wm MAWJearmer MOmM'eZ/ Dec. 20, 1949 L. JBULLIET 2,492,092

MATERIAL WORKING APPARATUS I Filed Feb. 13, 1946 8 Sheets-Sheet 'rPatented Dec. 20,1949

UNITED STATES PATENT OFFICE MATERIAL WORKING APPARATUS tion of IllinoisApplication February 13, 1946, Serial No. 647,378

This invention relates to material working apparatus, and concernsparticularly means and methods of control for machine tools and thelike, whereby to efiect the accurate control of machining operationsperformed upon a work piece.

In the particular illustrative embodiment hereinafter to be set forth,the invention concerns specifically the operation and control of amachine tool, such for example'as a drill unit, for effecting the weightbalance control of a work piece.

In the balancing of crank shafts, or other rotatable machine parts, itis customary to mount the work piece into a balancing machine andsubject it to high speed rotation, simulating conditions encountered inthe ultimate operation of the part inservice. The irregularity, or outof balance condition of the work piece is recorded upon suitable gaugingdevices associated with the balancing machine. Correction or balancingof the work piece is then effected by removing a predetermined quantityof metal therefrom in a particular location on the part, so as to bringit into the proper balanced or desired Weight condition. The metalremoving operations may be effected by various machine tool operationssuch as, for example, by drilling, or milling, or the like.

For best results a high degree of accuracy is required in the control ofthe metal removing machine tool, so that an accurately predeterminedweight of metal will be removed from the Work piece at the desiredpoint. The diiliculties are generally further magnified due to theirregularities in shape of the cutting tool which eiiects the metalremoval. Thus for example a drill, providedwith a pointed end, willremove a constantly increasing volume of metal from the work piece inproportion to linear tool displacement until the tool point iscompletely embedded into the work, after which there will be a directproportional relation between volume or weight removal and tool lineardisplacement.

' In accordance with the present invention improved means and methodsare provided for effecting the accurate control of a machine tool, suchfor example as a drill unit, whereby to accurately control the limits ofa machining operation effected upona work piece. The invention furtherprovides improved means and methods forlautomatically setting thecontrols of the machine tool from a remote point, in accordance with thecontrol limits required; and further 1 Claim. gel. 77-5) trol of thecutting tool whereby weight settings on the controls of the machine areautomatically translated into the proper tool displacements, so as tocompensate for irregularities in tool shape.

and the like, whereby to accurately predeterprovides for the automatictranslation and con- 55 unit;

mine the extent and mode of the cutting operation.

A further object oi. the invention is to provide improved means andmethods for efiecting the machine operation by remote control.

A further object of the invention is to provide improved means andmethods for automatically translating a control setting calibrated inone function, as for example weight, into tool movement in anotherfunction, as for example linear travel.

A still further object of the invention is to provide an improvedtranslating and calculating mechanism, of the general type set forth;

Various other objects, advantages and features of the invention will beapparent from the following specification when taken in connection withthe accompanying drawings, wherein certain preferred embodiments are setforth for purposes of illustration.

In the drawings, wherein like reference numerals refer to like partsthroughout:

Fig. l is a general assembly view', diagrammatic in form, of a balancingmachine and machine tool installation constructed in accordance with andembodying the principles of the invention;

Fig. 2 is a diagrammatic view of the hydraulic control circuit for themachine tool, which comprises a drill unit in the particular embodimentset forth;

Fig. 3 is a side elevation of the drill unit;

Fig. 4 is a top view, partly in section, of the control mechanismforming a part or the drill Fig. 5 is a side view of the controlmechanism shown in Fig. 4;

Fig. 6 is an enlarged right end view of the control mechanism, as viewedon the line B6 trol mechanism taken as indicated by the line 99 of Fig.4;

Fig. 10 is an enlarged transverse sectional view taken as indicated bythe line ld-JEI of Fig. 4;

Fig. 11 is an enlarged detail view of the tool spindle forming a part ofthe drill unit of Fig. 3;

Fig. 12 illustrates a modified embodiment employing pressurecontrol inplace of the form of tool spindle shown in Fig. 11;

Figs. 13 and 14 illustrate modified arrange ments omitting the remotecontrol;

Fig. 15 is a wiring layout for the control panel of the drill unit;

Fig. 16 is a schematic layoutof thewiring at the various controlstations and parts; and

Fig. 17 is a line diagram of the complete electric circuit.

As previously indicated, the invention is herein shown applied to acombined balancing machine V General .machine. structures and mode ofoperation Referring more specifically to the drawings, and first to Fig.1, the installation shown comprise sa balancing machinediagrannnatically increated; 2.1150, and a machine tool, specifically adrill "unit, remotely disposed in respect to the balancing machineandjindicated by the numeral 52,; 'Theniachines are interconnected by anelectric cable'li l, and may be located in the same room, or indifferent room, as desired.

The balancingmachine may be of any suitable.

form and construction conventionally used in the balancing of machineparts such as crank shafts, the details ofv the machine forming no partof the pr'esen't invention. As previously indicated, such machines areprovided with means for mounting and rotating the crank shaft or otherpart to be tested,the out of balance condition of the part beingindicated by suitable dials associated with th'e'niachine, for exampleas indicated at 5B.

The balancing machine includes a panel boar-d 58 having an indicatorlamp 0, a calibrated dial knob 62 and a control push button (it for useby the operator of the balancing machine. In operation, after testing aparticular work piece, the balancing machine operator adjusts the dialknob 62'toa position indicative of the amount of out ofbalance in thework piece, which constitutes a measure of the weight of material to beremoved therefrom. He then presses the push button 64, which indicatesthat the setting has been made. During the adjustment of the knob 62 andthe operation of the button 64, the drilling machine 52 may be machininga previous workpiece or doing any other desired drilling operation.

Thedrilling machine includes a control panel 66 having anindicator lamp653, a Cycle start push button it, a Transfer push button it, and."certain other push buttons later to be described.

Theoperator of the drilling machine transfers the setting from dial knob'52 into the drilling machine control mechanism by pressing the Transferpush button '12 after the drilling machine has completed its previousdrilling operation. The indicator lamps 6E! and 68 become lighted andremain lighted during the transfer operation, indicating to bothoperators that a transfer from the balancing machine to the controlmechanism of the drilling machine is being effected. Afterthe balancetested work piece has been removed from the balancing machine andmounted in the drilling machine, the drilling machine operator theninitiates the automatic drilling operation, in accordance with thecontrol'mechanism setting, by depressing the Cycle start button ill. Thedrilling machine will thereupon operate automatically to remove thepredetermined weight of material from the work The drilling machine andits hydrauliccontrol circuits are shown in Figs. 2 and 3. The details ofthe drilling machine also form no part of the present invention. Themachine may, for ciample, be of the typeshown in the patent tp,

E. J. Svenson, No. 2,178,364,.

As shown in Fig. 3, the machine CQmpli S,,

a bed '55 having a work support 16, ,forsupporting the Work piece, suchas indicated at 18. Ahead;

stock 8b] is provided upon whichis mounted a prime mover or electricmotorTSZoperable'ftO r01,

tate the tool through a belt drive 8.4.,{and n59;

operable to drive the pumps forminga partof the, hydraulicpropellingcircuit for the machine.

shownin Fig. 2, these pumps. may comprise. .a low pressure, high volumegear pump. asfan'a a variable displacement low volume and'high pres}.sure plunger pump 88.. The rotatable tool,,90. is carried by areciprocable headstructure SZ, which.

as fully explained in saidPatent No 2,1 78,1164,v

is reciprocated longitudinallyrelative, to the main head frame at rapidtraversev and [feedingspeeds by a hydraulic actuator comprising acylinder land a piston 96,. Fig. 2.

A control valve 88, Figs. .2 and. .3, is ;pr.o vide d.

for controlling the movements of the hydraulic actuator piston. Thecontrol valve is provided with a shiftable valve member. lflfladaptedjoractuation by a lever I62 fixed to a pivotlshaftl Externally of thevalve. body .thisfpivot s carries an arm H06. operable by an .-.electromagnet.

508, and a pairof cams 1 l0 and. H2 opremable re v spectively, by a feeddog lHland a stop adjustably carried by a dogbar ltd-secured and movablewith the reciprocable toolheadfllz The valve structure, furtherlincludes a shiftable, piston E20 carried by a stern I22}proiecting;from.the valvestructure andarrangedlfor operation by an. electromagnet 124.

In operation, and as, is more particularly.- pointed out, in. saidPatent No, 2,178,36 i, whenthe valve member Hill-is shiftedto'the leftasseen reservoir 26 through line I28, and beingprm polled by thegearpump86-throughtheva1ve. and to-the actuator through. theline I30.- The.v

return fluid from the. actuator passes through.

ne. .I 32; he valve, and thenback to the reservoir through line I34 at aback pressure determined by the orifice device I36. As the piston movesaway from the port I38, fluid from the plunger pump also circulates tothe actuator through line I40 and from the actuator through line I42,whereby to augment the piston travel speed.

Shortly prior to the time the tool engages the work, the feed dog I I4shifts the valve member I to its neutral position shown in Fig. 2,whereupon fluid from the gear pump circulates through the valve and isreturned through line I34 without passing to the actuator. The actuatoraccordingly progresses under propulsion of the pump 88 at thepredetermined feeding rate thereof.

At the end of the cutting or drilling movement, to effect the reversalofthe tool head, the solenoid I24 is energized to project the piston I20to the left as seen in Fig. 2. As is more particularly pointed out insaid Patent No. 2,178,364, this causes an interconnection of the valvechamber I44 with the reservoir through the pressure relief line I46,whereby to unbalance the valve I09 causing it to be shifted rapidly tothe right or to a Reverse position. Fluid from the gear pump 86 is nowtransmitted from the valve 98 to the actuator through the line I32,causing reversal of the actuator until the stop dog II6 again shifts thevalve I00 to its neutral or central position whereupon fluid from thegear pump again circulates through the valve structure withouttransmission to the actuator, and fluid from the plunger pump circulatesthrough the actuator through port I48, and the actuator piston remainsat rest in its starting position.

The control mechanism hereinafter to be described is provided foraccurately controlling the precise time of operation of the reversingelectromagnet I24, so as to cause the drill to be withdrawn after it hasremoved an accurately predetermined volume or weight of metal from thework piece.

This control mechanism includes a series of control devices within thecontrol box I50 and the control panel 66 previously described. It also 5includes a spindle structure I52, Fig. 3, which has a switch operated atthe precise instant that the tool engages the work; a control switch I54operated from the dog slide I I8 through a switch arm I56 as the dogslide moves to the right or away from home position; and aself-synchronous transmitter I58 connected to and operated from a gearI60 engageable with a rack I62 fixed to the dog bar. The transmitter I58is of the type known as a Selsyn or Teletorque device. A similar Selsynor Teletorque transmitter I64, Fig. 1, is connected to and operated bythe control knob 62 of the balancing machine control panel.

Spindle control switch The spindle control switch structure I52 is shownin detail in Fig. 11.

As will be understood, the time of engagement between the tool and thework will vary in accordance with the setting of the work piece upon thework support I6, and also in accordance with irregularities in thesurface contours of the work piece. The purpose of the switch structureI52 is to determine accurately the time of engagement between the tooland the work, so that the point of tool reversal may be accuratelycalculated therefrom.

The spindle switch structure I52, as shown in Fig. "lLcomprises a mainhousing I66, theend til I68 of which is arranged to be carried by thereciprocable tool head 92. At its opposite end the housing slidablycarries an adapter I10 which supports the drill 90. The adapter isthreaded at its outer end I12 and adjustably carries a nut H4. The nutis arranged to bear against the end face of the housing I66, or againstthe inwardly projecting flange portion of an adapter ring I16 threadedonto the housing end. The annular channel I'IB defined by the adapterring slightly wider than nut I14, whereby to provide a slight spacing asindicated at I80 between the nut and the housing end when the nutengages the adapter ring flange. I

A compression spring I82 bears against th adapter so as normally to urgeit to the right, to the limitof travel allowed by the nut, as shown inFig. 11. The spring pressure is adjustable by a screw threaded plugmember I84. A key I86 precludes rotation of the adapter I'l0 relative tothe housing.

A switch structure of any approved type but preferably of the typeshownin Fig. 9 of the copending application of L. J. Bulliet, Serial No.569,027, filed December 20, 1944, and comprising a body portion I88 anda shiftable plunger I90 therein, is carried by the spindle structure.The switch is normally closed, when the parts are in the position shownin Fig. 11, and is arranged to be shifted to open position upon ashifting of the adapter and the plunger I90 engaged thereby to the leftagainst the action of spring I82 and relative to the switch body as thetool engages the work piece. The switch is opened just prior to the timethat the nut I14 engages the end face of the housing I66 to absorb thetool thrust. One contact of the switch is grounded to the spindle, andthe other contact thereof is connected by means of an electric wire I92to a metal ring I94 insulated from the housing and held in position by aretainer ring I96. A brush I98, Fig. 3, carried by but insulated fromthe head 92, provides a pick-up from the ring I94 during spindlerotation.

It will be seen that by the arrangement thus provided the normallyclosed switch structure I88-l 90 is arranged to be opened accurately andimmediately'as the tool and work become engaged.

Tool reversal control structure ated transmitter I58, whenever thereceivers are in electrical connection therewith. The receiver rotorsare so connected that they are both operated in the same direction, forexample clockwise as viewed in Fig. 6, as the transmitter I58 isoperated by a work approaching movement of 200.-- 'A shaft H2 is fixedto the housing 206 and movesttherewith; As best: shown in-u'l 'igs. Sand8, the housing ,26; has fixed thereto a contact plate 2 I4 carrying aseriesoi four. concentric-"slip ringsz2i6, 12IB, 226a and 222 which areengaged, respectively; by a. series of four spring pressed brushes 2 l6a, 2 l 8a.,226a .and222a, mounted within the pedestal 268;. thearrangement thus being suchgthat. the receiveris maintained in properelectrical contact with itsactuating circuits in any position. ofhousing rotation.

As'best shown-in Figs. 5 and 7, the rotorofi the-receiver; 2.62.:isconnected to a shaft 224,-the end of which carries a transverselypositionedarm 226 having a contact wire or finger-22B of a shape asshown. A hub extension of-the arm 226 carries; a .damper wheel 236loosely journalled thereon.. This damper wheel-is held fromaxialdisplacement byv means of a set. screw 232=carried by. the Wheeland loosely engaging an annular groove. in thehub extension, thearrangement thus being such that the damper wheel isprevented from axialshifting but is free to move rotatably relative to the arm 226 and. itsconnected shaft 224. The damper wheel, mounted, as thus, provided,reduces vibration of the shaft 224, due to, any sudden starting,stopping, or speed changes.

The housing 234 of the receiver 204 is fixed against rotationalmovement, but is arranged for limited axial movement within a bracketstructure carried by the base plate 260 and consisting of a front plateportion 236 and a rear yoke portion 238. As best shown in Figs. 4, 5 and6-, thereceiver housing Nil-carries a plate 240-hav-ing oppositelypositioned bosses 242 and 244-'within which are pinned a pair of shafts246. Theseshafts are longitudinally slidable within the plate 236 andthe upstanding arms of the yoke'memher 238, and each shaft is embracedby a com pression spring 248 which normally urges the receiver housingto the left as seen in-Figs; 4 and 5 so as to bring the bosses 242 and244 into en-- gagement with the fixed bracket platev 236, as

shown.

The rotor; of the receiver 204. has fixedthereto a transverselyextending arm 250, similar to. the arm 226, previously described, thearmcarrying a contact finger 2552, as shown, arranged for cooperationwith the contact finger 228 previously: described. The hub portion ofthe arm 256 carries a loosely'journalled damper wheel 254, in the mannerand for the purpose of the damper wheel 239, previously described.

The plate 249 has a depending extension to- Whichis secured one end of atension spring256, the; oppositeend of. which is connected to.thearmatureof an, electromagnet 258.: When the electromagnetisenergized, the plate 240andtheconnected receiver housing 23.4 is,drawnto. the right asseen; in Fig. 5, guided by the shafts246; until thearm 2 56 engages the fixed'bracket plate. 236. In this position of theparts'thecontact. fingers 1228 and 252 are positionedfor abutting.contact upon relative rotation of. the two receiver: rotors, asdistinguished from the position of the parts illustrated inFig. 5,wherein the fingers may rotate relative to each other without anyphysical; or electrical contact.

As will be more particularly described in the. statement of operationhereinaiterto beset forth, during the time that the tool isapproaching-the: workpiece, and prior to contact therewith-, theelectromagnet 258 is deenergizedand the rotors; of both receivers 262and 2-64 are electricallyjcon rnected with the-transmitterg I58.forzmfivement;

therewith y-so that no relative motion occurs between thecontact-fingers228 and 252 1 Asthe tool- -enga-ges the work, and the lnormall-y cl'osedspindle switch I 88- I 90 is opened, the I rotor of the receiver-"204is-disconnected from the transmitter, electromagnet 258 isenergized tobring the-contact-fingers 228 and 252 into alignment; and-simultaneouslythe axial movement-of the armc256 -also serves-to prevent furtherrotation of the arm I immediately as it engages the bracket plate 236; 1As thetcol continues to penetrate the workpiece, the contact finger 228continues to moveawith the forward projection of the tool; until thecontact fingers 228' and 252 come into engagement, whereupon electricalcircuits are actuated to energize the reverse solenoid I24, Fig; 3,andretract-the tool. I

As: will be understood, the rotatable position oil the receiver housing206 determinesthe initial angular spacedrelationship between the contactfingers 228 and 252 (for any given-electrical interconnection betweenthe rotors of thetransmitter and the receivers), the receiver housingposition thus presetting the amount of tool penetration.

: The means for setting the angular position of the receiver housing 2%,and its connected shaft 2 I2, will now be described.

Remote control, mechanism Aself synchronous receiver-26!] of the Sel'synor Teletorque type has its rotor electrically interconnected with therotor of the balance machine transmitter I64, in the same manner. thatthe rotors of the receivers; 2il2and 234 are interconnected with therotor of the drill unit dog slide transmitter I558. The rotor of thereceiver 26': carries an arm 252 having a contact finger 264 thearrangement being similar to the ar rangement of the arm and finger250252; pres viouslyldescribed. Thearm hub also looselycarries a damperwheel 2%, for the purpose pre viously described. The housing 268 of thereceiveri 266is mounted for limited axial movement. within its framesupport bracket 210, under .2. actuation-of an electromagnet 212, in thesame mannerasthe receiver housing 234, previously described. When-theparts are in the position lustratedinFig. 5, the contact finger 264' mayrotatel. freely without engagement with its co,-

. operatingcontact'finger 214, but when the electromagnet. .2'I-2 isenergized, the arm262 is drawn; to: .theleft as seen in Fig. 5, lockingthe arm againstrotation by reason of its engagement with the-.gframeplate 216, and also aligning the con-- tact fingers 264and2-14 forabutting engagement; Whenthe. parts-are in the position shown in Fig. 5,:andzprior. to'energization of the electromagnet' 2,1 2; .;the rotatableadjustment of the arm 262 will be effected in accordance with thesetting-of 1 the knob 62, Fig.1, ofthe self-synchronous transmitter I64.

The lcon-tactfinger 2I4Sis carried byan arm-218 fixed to a shaft 286form-ing-onepart of a differentialgearing structure, and'translatingmech toashaitZM forming another'part of this differential gearing, thislatter shaft being coupled with-- the; shaft 2 I 2 by means ofa suitablecouplingconnection 286.

Theis iaft 284 carriesv agear- 286: which meshes with a;gear29lls-secured tolthe zendzofanelongated The structure and functionof this" 9 drive shaft 292. The shaft 292 is arranged to be driven froman electric motor 294 through a suitable reduction gearing as indicatedat 296. It will be seen that by reason of the construction provided, asthe motor 294 is operated rotation is imparted to the shaft 284, whichthrough the differential gearing and translating mechanism 282 impartsrotation to the shaft 280, so as to rotatably drive the contact finger214. As best shown in Fig. 9, the drive shaft 298 of the electric motor294 carries a brake disc 300. This disc is adapted to be engaged bybrake shoe 302 fastened to one end of a pivot arm 304, the opposite endof which is pivotally connected to the armature 306 of an electromagnet308. A spring 3|0 normally holds the brake shoe 302 in engagement withthe disc 300, whereby to hold the motor drive shaft 298 againstoperation. The electromagnet 308 is energized to disengage the brakesimultaneously with the energization of the motor 294, and isdeenergized to apply the brake simultaneously with the deenergization ofthe motor.

As best shown in Figs. 5 and 10, the support bracket 3| 2 for thedifferential and translating mechanism carries on one face thereof aswitch block 314 having a switch arm 316 which is adapted to bemomentarily closed by the contact finger 214 as it passes the switchblock.

In the operation of the remote control mechanism, the rotor arm 262 ofthe receiver 260 is normally in the position shown in Fig. 5, at whichtime any adjustment of the balance machine setting knob 62 will becorrespondingly transmitted to the arm 262 to effect its rotatablepositioning. The full range of adjustment of the arm 262 comprisesapproximately 330, the contact finger 264 of the arm never moving into aposition directly opposite the switch structure 3 !4. As has beenpreviously brought out, the balance machine transmitter knob 62 may befreely adjusted during the time that the drilling machine is inoperation upon a previous work piece.

When it is desired to transfer or fix the setting of the arm 262 intothe drilling machine tool depth control mechanism the Transfer button 12is operated as previously described. This energizes the motor 294 andthe electromagnet 308, causing operation of the motor to rotate shafts284 and 280. As the contact finger 214 engages the switch arm M6, thesolenoid 212 is energized shifting arm 262 to the left as seen in Fig.5. thus locking the arm in its rotatable adjusted position and bringingthe contact fingers 264 and 214 into alignment. It will be noted thatthe energization of solenoid 212 occurs when the finger 214 is oppositethe switch 3i4, a zone into which the contact finger 264 never moves.Accordingly it is insured that the contact fingers cannot be in axialalignment when the finger 264 is axially shifted,-

which might result in improper operation of the parts. The rotation ofarm 218 continues until the contact fingers 214 and 264 are brought intoengagement, whereupon the motor 294 and the brake solenoid 308 aredeenergized, thus positioning the shaft 284, and the shaft 2l2 coupledthereto, into desired position. As previously described, the setting ofshaft 2l2 determines the rotatable positioning of the housing 206 ofreceiver 202, which in turn determines the depth of the tool cut.

Translating mechanism 280, is in terms of the weight of metal to beremoved by the drill. The setting of shaft 284 and connected shaft 212,however, must be in terms of the desired lineal penetration of the toolinto the work. Due to the fact that the tool is provided with a point onits end, and thus is of irregular shape, a direct proportionalrelationship does not exist between the weight and lineal penetrationfactors. The purpose of the translating mechanism is to calculate andtranslate the weight setting into lineal penetration terms.

Shafts 280 and 284 are provided, respectively, on their ends with bevelgears 3l8 and 320. As best shown in Fig. 4, these bevel gears mesh witha pair of bevel gears 322 carried by a rotatable cage 324 of adifferential gearing structure. The cage is fixed to a plate 325 looselyjournalled on the shaft 280, said plate having fixed thereto a gear 326,Figs. 4 and 10, meshing with a gear 328, the latter gear being fixed toone end of a shaft 330 journalled in the frame structure 3 l 2. The endof the shaft 330, opposite to the gear 328, carries a cam follower arm332 having a follower roller 334 on its end, the arm being spring urgedby a tension spring 336 so that the follower roller is maintained inengagement with a cam 338, Figs. 4, 5 and 10. This cam is fixed to theshaft 284, and hence is rotatable relative to the differential cage 324,but is rabbeted to form a journal bearing therefor.

In the operation of the translating mechanism the gear 288 and shaft 284will be operated by the motor 294 during the transfer setting operation,as previously described. Rotation of shaft 284 causes rotation of bevelgear 320 and of the cam 338, both of which are fixed on the shaft.Rotation of the cam acts through the cam follower arm 332 and shaft 330to impart a predetermined rotational movement to the gear 326 and thediiferential cage 324 to which this latter gear is fixed. Inasmuch asthe movement imparted to the bevel gear 3| 8 and its connected shaft 280is the summation of the movements of the differential cage and the bevelgear 320, it will be seen that the variation in movement between theshafts 280 and 284, from a direct proportional relationship, isdetermined by the contour of the cam 338. If the cam contour iscircular, the two shafts will move in direct proportional relationship,whereas any rise or fall in the cam will produce a difference.

The contour of the cam will be empirically determined in accordance withthe requirements of any installation, and a different cam substitutedfor each tool. The cam 338, as shown in Fig. 10, effects the propercalculation and translation from weight to linear displacement, inconnection with the particular pointed drill 90 of Fig. 3. In thisconnection it will be noted that the cam has a tapered surface 338aoperable in respect to the drill point, and a substantially circularportion 33% operable in respect to the drill body. The cam portion 3380operates when the contact finger 214 is in the zone of the switch 314 toreturn the cam follower to initial calculating position. Inasmuch as thesame is fixed to the shaft 284 which is in turn fixed to the shaft 2I2and in geared relationship with the shaft 280, the proper relativepositioning of the parts is continuously preserved.

Electrical structures eneaoea 1.11 at the. balancing machine-controlpanel .58; :at the drilling machinetcontrol panel -56, and .upon thedrilling machinestructure; Fig. .17. ,is a line diagram of theentireelectr-icalcircuit.

Corresponding reference .numerals. 3-9 and .l I--2.l appear in Figs.l5-l7so that eachterminal pointas set forth in Fig. 1'7 may-be readilyfound inFigslfi or 16. As will be understood, the elementsof Fig. areinterconnected'to those .of

Fig...16 through the intermediary of the terminal connector stripttt,Fig. 15.

It,is believed that the velectricalcircuit will-be best understood by.means of. .a detailed: descriptionof the machineoperation, referringparticularly to the line diagram, Fig. 1'2.

Operation 1 To'put the machineiintooperation; the drilling:machine.operatorsflrst closes. the manual dis- -connect switch tflwhich-connects the-circuit with a suitable source zofelectricalpower;.such for example as 8-phase 440 :yoltalternetting current. Theclosingriof-rswitch M2 energizes the control .circuit at reducedvoltage,through the action oftransformerzfi i' i..The'zdril'lingmach-ine I operator then presses thefRun pushxbutton t itwhich energizes the poll of .a master relay: 348. One-contact348a.-oflthiscrelay: closes and establishes a'rholding circuit raroundithe push button 346, which may be only momentarily depressed. Another.contact 't itb'of the master relay 348'-a*lso;closes"whereby to:supply'the current from the ;-transformer"secondary through thecontacts 348a and 8548b tothe control circuit of the machine, and :moreparticularly to the main supply wires l'ie-and lfi. ThezdlillingInachine-operator .next momentarily pushes the istarthpush buttonll'which picks up or energizes the motor starter relay 352. One set ofcontacts ;35 2a"close to establish a. holding circuit for the motorstarter. Additional contacts 35% areasimultaneously closed-to: apply the440 :volt l-inecurrent to-theimotor .82. The :motor thereupon startsdriving the drillingtool-"spindle and the pumps .83 =anda88aof the:drilling machine hydraulic circuit; as previouslydescribed.

It will beseenthat theself-synchronou's transmitterultt haslitsirotorwindings interconnected withithereceivcr tilt, aspreviously described,so that; while the-contrfolcircuit wires. -11. and I9 areenergizedaany.movementiimparted to the rotor of thertransmitten will becorrespondingly imparted to the rotor of thereceiver.

--'After the; setting of the transmitter :knob. 52 hascbeen made,the-operator atthe balancing machine presses his push button .64 toindicate that-he has completed hissetting; Momentary pressing .of this.push button energizes the coil of a relay 354 which thereupon closesitscontacts 3:54aand 354i). The closing :o-f contactta establishes; aholding vcircuit :around the push button 6 3.

Thetoregoing operations; may beieifected while the. dril1ing.,machine:is .machining' a previous work piece, as hasbeendescribed. At therenclof :the machining; operation the I operator at r the drilling machinepresses his Transfer push bu ton i2. .Momentary-closingof this.pushbutton energizes the coil :of a relay .356 which thereupon closesits contacts 356a and 35Gb. The-closingof contacts 355a establishes aholding. circuit around the push button '12.

Inasmuch as contacts 354band l355a .arcrnow bothclosedpcurrenti'stransmitted to the transferv motor 29 i and tothe brake releasesolenoid 308,

the motor thereupon operating to rotate-shafts .2B l-and Edit, aspreviously described. Current is simultaneously transmitted to thetwolampstfl and 68 whereby to indicate to both operators that a transferof the-control setting is being effected.

When the contact finger 214 engages and. closes switch 316, thecoil ofarelay 358 is energized which thereupon closes its contacts 358a and.3581). Closing-of contacts 358a establishes a holding circuit aroundthe switchtld. Closing of contacts 35% effects the energization ofsolenoid :212 which thereupon-operates as previously -.described toshift the contactfinger2t4 to the left as seen in Fig. 5, into the pathof travel of-the moving contact finger 214.

When the contact fingers 264 and 214 are brought into engagement acoldcathode gaseous discharge tube 360 effects. the energization of a relayas shown at .362. Normally, and prior :-to engagement of the contactfingers 264 and 214, it will be seen, Fig. 17, that'the grid or startingelectrode of the tube "380 is connected to the line 5-1 through aresistor 364. The tube cathodeis also connected to the same-power lineI! through a resistor 366 and the coil of relay 362. Thus the tubecathode and grid are at the same voltage and the tube does not conductcurrent. When the fingers 2&4 and-2M make contact, the resistor .364 andaresistor3 58 form a voltage divider between the power lines, with'thetube grid connected therebetween. The resistance of resistor .3.58-isless than that of resistor '364'so that the grid-is-nownear the tubeanode in potential, and the tube conducts current, thus energizing thecoil of relay 362. The resistor 366 forms a cur rent limiting elementfor the tube, and the capacitor-310 is a filter -toreduce the ripple in(the current rectified bythe tube-36ll. The capacitor 3121s a filteragainst parasitic surges. The total resistanceofthe resistors 364 and368 is suiTi ciently high, one megohm or more, to prevent arcing at thecontact fingers 264 and 214.

-Energization of: relay 362 closes its contacts 362a, forming a holdingcircuit to keep the tube conducting and therelay fitlenergized. Theenergization of-theurelay zalso'opens a pair of normally closed contacts35% which deenergizes-the transfer motor. 294- and itsbrakesolenoid-358. Thus themotor is quickly deenergized and brakedintostopped position immediately upon the'contacting of the fingers-2&4and 214, whereby. toaccurately position the shaft 280 in accordance withtheisetting fromthe remote balancing machine control knob 62.

"Through the action of the calculating and translating mechanism.previously described," as the shaft 2801s set to position, the shaft 284is simultaneously brought into the proper position tovpredeterminethedepth of tool penetration in accordance with'the weightsetting of the knob 62.

Opening'of relay contactBBZb also extinguishers lamps 60 and 68 anddeenergizesrelays.354,'356 and-358. Upon deenergization' of. theserelays, contacts 3562b and 358bare opened. The opening of'contact-356bbreaks the holding circuit for the tube .366, and the-opening ofcontacts 35th .deenergizesisolenoid 272 which allows the housing 268 ofthereceiver 266 to move back to normal position. The operation of theremote control to effect the setting of the shaft 2l2 is now complete.

. To eflect. the drilling operation, the drilling machine operator nowmomentarilypresses "the "Cycle start" push button 10. This energizes thesolenoid I08 which shifts the hydraulic control valve I to rapidapproach position as'previously described. As the approach movement ofthe tool begins, the limit switch I54 is shifted opening its contactsI54a and closing its contacts I541). Opening of contacts [54adeenergizes the solenoid I08 in case the Cycle start push button has notbeen released. As shown in Fig. 17, the Selsyn transmitter I58 isinterconnected with the receivers 202 and 204, as previously described,so that the motion of the transmitter, due to the forward progress ofthe tool, is proportionally transmitted to both receiver rotors.

Just prior to the engagement of the tool with the work the feed dog H4,Fig. 3, operates to reduce the travel of the head 92 to a feeding speed.

Precisely as the tool engages the work, the normally closed spindleswitch I88--I 90 is opened as previously described. As has been pointedout, one contact of this switch is grounded to the spindle and thus tothe frame of the machine. The control wire I9 is also grounded, as shownin Fig. 17.

A cold cathode gaseous discharge tube 314 has its cathode connected tothe line I9 and its anode connected to the line I1 through a currentlimitins resistor 31B and the coil of a control relay 318. The grid orstarting electrode of the tube is connected between a pair of resistors380 and 382 forming a voltage divider between the lines I1 and I9. Thespindle switch I88-I 80 is also connected between the resistors 380 and382 through a third resistor 384. The resistance of resistors 382 and384 in parallel is considerably lower than the resistance of resistor380. Consequently, so long as switch I88-I90 remains closed, the voltageof the tube grid is very close to that of the cathode and the tube 314does not conduct current. As the switch I88-I90 is opened, uponengagement of the tool with the work, resistance 384 is cut out.Resistor 382 alone has a much higher resistance than resistor 380 sothat the voltage of the tube grid now becomes very near that of the tubeanode and the tube conducts current, energizing the relay 318. Thecapacitor 306 acts to reduce current ripple, as in the case of thecapacitor 310 previously described. The combined resistances of theresistors 380 and 384 is kept sufficiently high to prevent any arcing atthe switch I88-I80.

The energizing of relay 318 causes it to close its contacts 318a wherebyto energize a relay 388. The energization of this latter relay causesthe closing of its contacts 388a and 3881). The closing of. contacts388?) effects the energization of the solenoid 258 which thereuponoperates to shift the contact finger 252 of the receiver 204 axially andarrest its rotation. The simultaneous closing of contact 388a energizesthe coil of a relay 390 which thereupon closes its contacts 390a and390b, and opens its normally closed contacts 3900 and 39011. The openingof these latter contacts, which occurs simultaneously with theenergizatlon of solenoid 258, disconnects receiver 204 from thetransmitter I58, the driving force for the receiver rotor thus beingdisconnected as the rotor is stopped and held in braked condition.

As the tool proceeds to cut into the work piece, the rotor of thereceiver 202 continues to move with the forward progress of the tool,and when the tool has penetrated to the proper depth, the fingers 252and 228 are brought into contact, as previously described. A coldcathode gaseous 14 discharge tube 392 has its anode connected to thecontrol circuit wire I9, and its cathode connected to the wire I1through a resistor 394' and. a control relay 396. The grid or startingelectrode of the tube is connected between a pair of resistors 398 and400, the arrangement being essentially similar to that previouslydescribed in reference to the tube 360. Prior to the contacting of thefingers 228 and 252, the tube grid and cathode are at the same voltageand the tube does not conduct current. When the fingers 228 and 252 makecontact, the tube fires in the same manner as previously described inreference to tube 360. Capacitors 402 and 404 are provided to efi'ectthe functions of capacitors 310 and 312, respectively,

previously described. Arcing at the contacts 228 and 252 is prevented asin the case of the contacts 264 and 214.

The firing of the tube energizes relay 386 which thereupon closes itscontacts 396a and 3961). The closing of contact 386a forms a holdingcircuit for the tube around the contact fingers 228 and 252. The closingof contact 3951) energizes the solenoid I24 which, as previouslydescribed, shifts the hydraulic control valve to its reverse position.The tool is thus immediately and accurately reversed precisely at thepoint of contact between the fingers 228 and 252.

As the tool starts away from the work, the spindle switch I88--I90recloses. This extinguishes the tube 314 and deenergizes the relay coil318 which thereupon opens its contacts 318d to deenergize the relay 388which thereupon opens its contacts 388a and 38%. Opening contact 388abreaks the original energizing circuit to the coil of relay 380, but thecontacts 390a, which are now closed, maintain the relay energized.Opening of contact 3881) deenergizes the solenoid 258 allowing the axialshifting of the housing of the receiver 204 to its normal position.

As the tool head 92 returns, the rotor of the receiver 202 operatestherewith whereas the rotor of receiver 204 remains stationary, thelatter being still disconnected from the transmitter I58. When the toolhead reaches home position, the stop dog H6 acts to neutralize thehydraulic control valve, and simultaneously the limit switch 154 isshifted to reopen its contacts I54b and close its contacts I54a. Openingcontacts I541) deenergizes the relay 390 which thereupon opens itscontacts 390a and 3901) and closes its normally closed contacts 390.0and 390d. The opening of contacts I54b also deenergizes the solenoidI24. The opening of contacts 39% extinguishes the tube 332, whichthereupon deenergizes relay 396 opening its contacts 385a and 3861). Theclosing of contacts 3800 and 390d reconnects the rotor windings ofreceiver 204 with the rotor windings of the transmitter I58, whereuponthe rotor of receiver 204 shifts to a position in synchronism with thatof the rotor of the transmitter.

It will be seen that due to the electrical contacts, the Selsynconnections, and the electronic tubes provided, rapid and accurateactuation of the control circuits is insured.

Depression of the Emergency push button 408 at any time during theforward motion of the tool will energize the solenoid I 24 causing thetool to be returned immediately. At the end of such emergency return,the action of the limit switch I54 restores all parts of the circuitready for a new cutting cycle.

Pressing of the Stop button 408 at any time will deenergize the coil ofmaster relay 848, causing the entire control circuit to be deenergized.

Modified arrangements =In Eigs. '12, 13 and 14 certain modifiedembodiments are shown.

A5 illustrated in Fig. 12', pressure control may be substituted for thetypeof spindle switch shown'in Fig; 11. As shown, a pressure switch,generally indicated by the 'numeral 510, may be interconnected with thepressure line 140 between the'feed pump 88 and the hydraulic actuator ofthe drilling'machine. The pressure switch may comprise a bellows 4l2interconnected withthe pressure line, and a switch structure 41 4operated thereby, the arrangement being such that the switch is openedas the pressure within the bel-- lows-exceeds a predetermined value.

Thenormally closed pressure switch of Fig. 12 may be substituted for thenormally closed spindle'switch IB8'- I% of Fig. 11, and interconnestedin'the electrical circuit in thesame manner. "By setting'the pressureswitch so that it opens by the inoreased-pressure'in theconduit t lflcccasioned by-the engagement of the tool with the worl -itwill be seenthat the pressure switch functions inthe same manner and for the'samepurposeas "the spindle switch structure previously described. It a snapaction pressure switch, with substantial contacts is used, the tube 314may, if-desired, be-eliminated, the pressure switch serving to-d-irectlyenergize and deenergize the rela'y 318.

-'In Fig. 1-3'an arrangement is shown whereby the settingof-shaft :2l2-may be efiected manually, by direct manual actuation, and not by remotecontrol. As-willbe'seen, a manual control knob' lifi maybe attached tothe end of the shaft 2P2, to eifect-the setting-thereof and control thetool depth penetration, by direct manual actuation'andcontrol.

In Fig, 14 a direct manual arrangement for effecting the setting ofshaft H2 is also shown, but in this instance also including thetranslating orcalculating mechanism 282, as previously described. *-Asshown, a manual control knob or handle 418- is-fixed to-the endof shaft280, in

16 substitution for 'the arm z la'previo'usly described; The remaihderof the parts may be arranged as previously described except that thegears 288 and 290, and their associated driving connections are notprovided.

It is obvious that various changes may be made in thespecific'embo'diments set forth without departing from the spirt'of theinvention. The invention is accordingly not to 'be limited to thespecific embodiments shown and described, but only as indicated in'thefollowing claim.

The invention is hereby claimed as follows:

A material working apparatus comprising a work support arranged tosupport a work piece, a tool support arranged to support aworking tool,means for shifting the toolsupport and work support relative to eachother to cause the tool to engage and machine the work, aselfsynohronous electric transmitter shiftahle by relative movementbetween the tool and work supports and proportional thereto, apair ofselfsyhchrohous electric reoeivers' each having an element driven by thetransmitter, a switch member carried by each receiver element, means forcontrolling the interconnection between the transmitter and the drivenelement of one receiver by the engagement of the toolwith the work, andmeans controlled by the-contacting 'of said switch-members forterminating the'mac'hining operation between" the tool and the workpiece.

LEANDER' JACKSON BU'LLIE'I'.

REFERENCES CITED The following references are of record inthe file ofthis patent:

UNITED STATES PATENTS Number Name Date 841,443 Richards Jan. 15, 19072,243,379 Johnson May 27, 1941 2,292,346 Pritchard -Aug. 11, 19422,324,727 Shart1e- July 20,1943 2,389,368 King -41---- Nov. 20, 19452,434,680 White 'et a1 Jan. 20, 1948

